Molecule of Life Finds New Uses in Microelectronics

A team of scientists has deployed DNA to create a circuit element capable of splitting and combining current—much like an adapter that can connect multiple appliances to a wall outlet.

A team of scientists has deployed DNA to create a circuit capable of splitting and combining current—much like an adapter that can connect multiple appliances to a wall outlet. (c)iStock/spainter_vfx

A team of scientists has deployed DNA to create a circuit element capable of splitting and combining current—much like an adapter that can connect multiple appliances to a wall outlet.

The creation, developed by researchers at NYU, Arizona State University, and Duke University, relies on DNA’s self-assembly properties and its ability to conduct electrical charge over long distances. These characteristics make it well-suited for multiple applications, including tiny electronic circuits and computing devices as well as nanorobots and new advances in photonics.

“It is well-known that DNA can be used as a wire to conduct current,” explains Nadrian Seeman, a professor of chemistry at NYU and the senior author of the research, which is reported in the journal Nature Nanotechnology. “DNA nanotechnology has risen in the last few years as a means of self-assembling objects, lattices, and devices, thereby enabling the organization of DNA into a variety of structural arrangements and making DNA a promising candidate for nanoscale circuitry.

“This advance shows that it is now possible to build DNA-based circuitry that entails multi-terminal circuitry, which provides the structural model for electrical networking and for control.”

Arizona State Professor Nongjian “N.J.” Tao, a co-author of the study, has been working on refining the ability of DNA to more stably and efficiently transport charge, an essential hurdle on the path to a new generation of biologically based devices.

“The ability of DNA to transport electrical charge has been under investigation for some time,” says Tao, who directs the university’s Biodesign Center for Bioelectronics and Biosensors. “Splitting and recombining current is a basic property of conventional electronic circuits. We’d like to mimic this ability in DNA, but until now, this has been quite challenging.”

Current splitting in DNA structures with three or more terminals is difficult as charge tends to dissipate rapidly at splitting junctions or convergence points.

In the new study, a special form, known as G-quadruplex (G4) DNA, is used to improve charge transport properties. G4 DNA is composed of four rather than two strands of DNA that contain only the base guanine.

“DNA is capable of conducting charge, but to be useful for nanoelectronics, it must be able to direct charge along more than one path by splitting or combining it,” says Peng Zhang, an assistant research professor of chemistry at Duke University and a co-author of the study. “We have solved this problem by using the guanine quadruplex (G4) in which a charge can arrive on a duplex on one side of this unit and go out either of two duplexes on the other side.”

“Various device-like functions have been reported for two-terminal single molecular junctions, but a practical circuit-like element requires three or more terminals for control and for electrical networking,” notes Seeman. “This work demonstrates that a strategically designed G-quadruplex motif can fulfill the critical requirements for moving beyond two-terminal functionality.”

“This is the first step needed to transport charge through a branching structure made exclusively of DNA,” Zhang adds. “It is likely that further steps will result in successful DNA-based nanoelectronics that include transistor-like devices in self-assembling ‘pre-programmed’ materials.”

The research team also consisted of Tao’s ASU colleagues, Limin Xiang and Yueqi Li; Ruojie Sha of NYU; and Chaoren Liu, Alexander Balaeff, Yuqi Zhang, and David N. Beratan of Duke University.

The work was supported by a grant from the Office of Naval Research (N00014-11-1-0729).